Electric heater.



PATENTED SEPT. 29, 1903.

J. H. HALLBERG. ELECTRIC HEATER.

AILPLIOATION FILED Nov. 8. 1902.

H0 MODEL.

WE "cams FUERS c0, PNOTO-LITNO. WASHINGTON, o c.

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. UNITED STATES Patented September 29, 1905.

R EN FEIQE- ELECTRIC HEATER.

SPECIFICATION forming part of Letters Patent No. 740,125, datedSeptember 29, 1903.

Application filed November 8,1902. Serial No. 130,566. (No model.)

To aZZ whom it may concern:

Be it known that I, JosEF I-IENRIK HALL- BERG, a citizen of the UnitedStates, and a resident of New York, in the county'of New York and Stateof New York, have invented certain new and useful ImprovcmentsinElectricHeaters, of which the following is a specificatiou.

This invention relates to improvements in electric heaters,'the mainobject of the invention being to convert electric energy into heatenergy in a more economical manner than it has heretofore been done.

Electrical apparatus as generally designed for the purpose of convertingelectric energy into heat usually belong to that class in which theelectric energy in passing through a medium develops heat as a result ofthe resistance of such medium to the passage of the electric currenttherethrough. The electric heater which I have devised is an improvedapparatus of the type in which the heat developed therein is derivedfrom the field of force surrounding an electrical conductor and isdeveloped in a medium which is placed in said field of force, but doesnot form part of the circuit of the electrical conductor. The conversionof electric energy into heat according to my system is thereforedependent upon the setting up of a field of force around an electricalconductor and upon the development of heat directly from the lines offorce of this field or from electric currents-that is, eddy currentsinduced by the lines of force of said field. In order to develop heatfrom these lines of force composing the field surrounding an electricalconductor, it is essential that the flow of these lines of force shallbe of varying intensity, and this is usually accomplished by varying theintensity of the flow of lines of force-that is, the intensity of theelectric current flowing in the electrical conductor about which suchfield of force is established. This variation of the intensity of theflow of the lines of force composing such field can be best obtained bypassing an alternating electric current through a conductor around whichit is desired'to establish sucha varying flow of lines of force, becausethe complete reversal of the flow of these lines at each alternationwill produce the heating effect in a heat-developing medium placed in ofmy invention.

such field so as to be traversed by said lines of force. If this mediumis a magnetic metal, the magneticlines of force which pass through themetal being completely reversed at each alternation of the electriccurrent will reverse the magnetization of each molecule of the metal ateach alternation of the electric current-thatis to say, the magneticlines of force will tend to turn the molecules of the metal first in onedirection and then in another in accordance with the direction of fiowof such lines of force, heat being produced in such metal by themolecular friction resulting from the rapid changes in the positions ofthe molecules. In electrical machinery the losses due to such heatingeffects are reduced to a minimum by the use of laminated cores, &c., andby employing agood quality of soft iron. In order to obtain the greatestheating edect, the metal to be heated should be in a solid mass andshould be relatively hard, hard cast iron and steel producing goodresults. For this reason in any type of heating device in which myinvention may be embodied in order to obtain the bestresuits theapparatus should be made of such material and the construction should besuch as to permit as many of the magnetic lines of force to be impressedas possible and should also be such as to retard as much as possible thereversal of the magnetization. These and other features of my inventionnot here inbefore referred to, but which will be hereinafter described,are illustrated in the accompanying drawings, in which- Figure 1 is afront elevation of a simple form of electric heater adapted for use onan ordinary house-circuit of an alternating-current system andillustrates one embodiment Fig. 2 is a vertical section of the same.Fig. 3 is a diagrammatic view of an ordinary alternatinglighting-circuitineluding a heater embodying my invention.

A field of force of varying intensity suitable for the development ofheat in accordance with my invention may be established in many ways,but preferably by means of an alternating electric current. Such acurrent will usually be derived from an alternating ICO vice, such as atransformer, the primary winding of which is indicated at i and thesecondary at 5. This transformer will effect the usual conversion of ahigh-tension current into one of lower potential for houselightingpurposes, the nature of the secondary circuit employed by me beingindicated by the presence therein of incandescent lamps 6, which,however, constitute no part of my invention.

One of the main elements of an electric heater adapted to develop heatenergy from the energy of a field of force is an electrical conductor orcoil, such as 7, through which an electric current flows and aroundwhich a field of force is established by such flow. The number of turnsof the coil 7 will be proportioned properly for the work to be done andalso to the available energy of the source of supply. The coil 7 may beconnected in circuit with the secondary through suitable binding-posts,such as 8 and 9, on another element of the heater.

As before stated, I prefer to employ a heater in which theheat-developing medium or metal is not -merely located in the field offorce, but forms part of a complete metallic circuit. One of theelements of such circuit is the core around which the coil or helix 7 iswound, and this core is a magnetic metal. ticular construction of thiscore may be varied at will, according to the character of the electricalapparatus in which it is desired to develop heat. In the constructionshown in the drawings, which illustratesa house-heater similar to aradiator of a steam-heating system, a tubular magnetic core, such as 10,is preferred in order to admit of the exposure of the largest area ofheated metal to upwardly flowing currents of air. The remainder of themetallic magnetic circuit of this type of electric heater may be formedby connecting with the tubular core 10 a tubular metallic magnetic shellof sufiicient size to surround the coil 7 and completely inclose saidcoil and its core. These two tubular magnetic shells 10 and 11 willusually be of similar cross-section, they being oblong in cross-sectionin the construction illustrated. Any suitable means may be employed forholding the core, coil, and the outer heat-developing shell 11 in theirproper relative po- The parsitions. When the parts are organized asillustrated in Fig. 2, it will be seen that both sides of each of saidshells are exposed to a current of air traveling upward through theheater and that three diiferent upwardlyfiowing currents of air aresimultaneously heated by the metallic surfaces to which they areexposed.

The particular construction of core shown herein is intended for usewith the particular type of electric heater illustrated and, as shown,constitutes a heat-developing solid mass of metal similar in itsfunctions to the outer shell or metallic body 11. In general, however,the medium or body outside the coil in an electric heater embodying myinvention is the principal medium in which the energy of the fieldof'force is converted into heat energy. When so placed, such outer solidbody or mass of magnetic metal forms part of a magnetic circuit, whichinthe preferred construction is a metallic circuit completed in anysuitable manner, in this case through metallic end pieces, such as acover 12 and a base 13, which form a metallic connection between theshells 10 and 11. The cover 12 and base 13 have openings therein,through which heated air may pass and cold air be drawn to take itsplace.

What I claim is In an electric heater, the combination with a base, ofan electric coil, and a metallic circuit embodying a tubular metalliccore through which a body of fluid may flow and a tubular metallic shellsurrounding said core and coil in the field of force of the coil forconverting energy of said field into heat energy said core and shellforming between them and around said coil an open channel in whichanother body of fluid may flow in contact with the core the coil and theshell and being mounted on said base and rising vertically therefrom toheat such fluid continuously and cause it to ascend.

Signed at New York, in the county of New York and State of New York,this 5th day of November, A. D. 1-002. I

JOSEF HENRIK IIALLBERG.

Witnesses:

I. WERTHEIMER, H. P. WELLMAN.

